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Endolysins are bacteriophage (or phage)-encoded enzymes that catalyse the peptidoglycan breakdown in the bacterial cell wall. The exogenous action of recombinant phage endolysins against Gram-positive organisms has been extensively studied. However, the outer membrane acts as a physical barrier when considering the use of recombinant endolysins to combat Gram-negative bacteria. This study aimed to evaluate the antimicrobial activity of the SAR-endolysin LysKpV475 against Gram-negative bacteria as single or combined therapies, using an outer membrane permeabilizer (polymyxin B) and a phage, free or immobilized in a pullulan matrix. In the first step, the endolysin LysKpV475 in solution, alone and combined with polymyxin B, was tested in vitro and in vivo against ten Gram-negative bacteria, including highly virulent strains and multidrug-resistant isolates. In the second step, the lyophilized LysKpV475 endolysin was combined with the phage phSE-5 and investigated, free or immobilized in a pullulan matrix, against Salmonella enterica subsp. enterica serovar Typhimurium ATCC 13311. The bacteriostatic action of purified LysKpV475 varied between 8.125 µgâ¯ml-1 against Pseudomonas aeruginosa ATCC 27853, 16.25 µgâ¯ml-1 against S. enterica Typhimurium ATCC 13311, and 32.50 µgâ¯ml-1 against Klebsiella pneumoniae ATCC BAA-2146 and Enterobacter cloacae P2224. LysKpV475 showed bactericidal activity only for P. aeruginosa ATCC 27853 (32.50 µgâ¯ml-1) and P. aeruginosa P2307 (65.00 µgâ¯ml-1) at the tested concentrations. The effect of the LysKpV475 combined with polymyxin B increased against K. pneumoniae ATCC BAA-2146 [fractional inhibitory concentration index (FICI) 0.34; a value lower than 1.0 indicates an additive/combined effect] and S. enterica Typhimurium ATCC 13311 (FICI 0.93). A synergistic effect against S. enterica Typhimurium was also observed when the lyophilized LysKpV475 at â MIC was combined with the phage phSE-5 (m.o.i. of 100). The lyophilized LysKpV475 immobilized in a pullulan matrix maintained a significant Salmonella reduction of 2 logs after 6 h of treatment. These results demonstrate the potential of SAR-endolysins, alone or in combination with other treatments, in the free form or immobilized in solid matrices, which paves the way for their application in different areas, such as in biocontrol at the food processing stage, biosanitation of food contact surfaces and biopreservation of processed food in active food packing.
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Antibacterianos , Endopeptidases , Glucanos , Polimixina B , Fagos de Salmonella , Endopeptidases/farmacologia , Endopeptidases/química , Endopeptidases/metabolismo , Polimixina B/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química , Fagos de Salmonella/genética , Fagos de Salmonella/fisiologia , Fagos de Salmonella/química , Glucanos/química , Glucanos/farmacologia , Animais , Testes de Sensibilidade Microbiana , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/virologia , Camundongos , Salmonella typhimurium/virologia , Salmonella typhimurium/efeitos dos fármacos , Bacteriófagos/fisiologia , Bacteriófagos/genética , Proteínas Virais/genética , Proteínas Virais/metabolismo , Proteínas Virais/farmacologia , Proteínas Virais/químicaRESUMO
The lack of effective treatment options for an increasing number of cancer cases highlights the need for new anticancer therapeutic strategies. Immunotherapy mediated by Salmonella enterica Typhimurium is a promising anticancer treatment. Candidate strains for anticancer therapy must be attenuated while retaining their antitumor activity. Here, we investigated the attenuation and antitumor efficacy of two S. enterica Typhimurium mutants, ΔtolRA and ΔihfABpmi, in a murine melanoma model. Results showed high attenuation of ΔtolRA in the Galleria mellonella model, and invasion and survival in tumor cells. However, it showed weak antitumor effects in vitro and in vivo. Contrastingly, lower attenuation of the attenuated ΔihfABpmi strain resulted in regression of tumor mass in all mice, approximately 6 days after the first treatment. The therapeutic response induced by ΔihfABpmi was accompanied with macrophage accumulation of antitumor phenotype (M1) and significant increase in the mRNAs of proinflammatory mediators (TNF-α, IL-6, and iNOS) and an apoptosis inducer (Bax). Our findings indicate that the attenuated ΔihfABpmi exerts its antitumor activity by inducing macrophage infiltration or reprogramming the immunosuppressed tumor microenvironment to an activated state, suggesting that attenuated S. enterica Typhimurium strains based on nucleoid-associated protein genes deletion could be immunotherapeutic against cancer.
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Salmonella typhimurium , Animais , Salmonella typhimurium/imunologia , Salmonella typhimurium/genética , Camundongos , Camundongos Endogâmicos C57BL , Melanoma/imunologia , Melanoma/genética , Melanoma/patologia , Imunoterapia/métodos , Macrófagos/imunologia , Macrófagos/metabolismo , Linhagem Celular Tumoral , Mutação , Feminino , Melanoma Experimental/imunologia , Melanoma Experimental/patologia , Melanoma Experimental/terapia , Modelos Animais de DoençasRESUMO
Conventional cancer therapies have many limitations. In the last decade, it has been suggested that bacteria-mediated immunotherapy may circumvent the restrictions of traditional treatments. For example, Salmonella enterica is the most promising bacteria for treating cancer due to its intrinsic abilities, such as killing tumor cells, targeting, penetrating, and proliferating into the tumor. S. enterica has been genetically modified to ensure safety and increase its intrinsic antitumor efficacy. This bacterium has been used as a vector for delivering anticancer agents and as a combination therapy with chemotherapy, radiotherapy, or photothermic. Recent studies have reported the antitumor efficacy of outer membrane vesicles (OMVs) derived from S. enterica. OMVs are considered safer than attenuated bacteria and can stimulate the immune system as they comprise most of the immunogens found on the surface of their parent bacteria. Furthermore, OMVs can also be used as nanocarriers for antitumor agents. This review describes the advances in S. enterica as immunotherapy against cancer and the mechanisms by which Salmonella fights cancer. We also highlight the use of OMVs as immunotherapy and nanocarriers of anticancer agents. OMVs derived from S. enterica are innovative and promising strategies requiring further investigation.
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Antineoplásicos , Neoplasias , Salmonella enterica , Salmonella typhimurium , Imunoterapia , Antineoplásicos/uso terapêutico , Neoplasias/terapiaRESUMO
Introduction: Bacteriophages infecting human pathogens have been considered potential biocontrol agents, and studying their genetic content is essential to their safe use in the food industry. Tequatrovirus ufvareg1 is a bacteriophage named UFV-AREG1, isolated from cowshed wastewater and previously tested for its ability to inhibit Escherichia coli O157:H7. Methods: T. ufvareg1 was previously isolated using E. coli O157:H7 (ATCC 43895) as a bacterial host. The same strain was used for bacteriophage propagation and the one-step growth curve. The genome of the T. ufvareg1 was sequenced using 305 Illumina HiSeq, and the genome comparison was calculated by VIRIDIC and VIPTree. Results: Here, we characterize its genome and compare it to other Tequatrovirus. T. ufvareg1 virions have an icosahedral head (114 x 86 nm) and a contracted tail (117 x 23 nm), with a latent period of 25 min, and an average burst size was 18 phage particles per infected E. coli cell. The genome of the bacteriophage T. ufvareg1 contains 268 coding DNA sequences (CDS) and ten tRNA genes distributed in both negative and positive strains. T. ufvareg1 genome also contains 40 promoters on its regulatory regions and two rho-independent terminators. T. ufvareg1 shares an average intergenomic similarity (VIRIDC) of 88.77% and an average genomic similarity score (VipTree) of 88.91% with eight four reference genomes for Tequatrovirus available in the NCBI RefSeq database. The pan-genomic analysis confirmed the high conservation of Tequatrovirus genomes. Among all CDS annotated in the T. ufvareg1 genome, there are 123 core genes, 38 softcore genes, 94 shell genes, and 13 cloud genes. None of 268 CDS was classified as being exclusive of T. ufvareg1. Conclusion: The results in this paper, combined with other previously published findings, indicate that T. ufvareg1 bacteriophage is a potential candidate for food protection against E. coli O157:H7 in foods.
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Bacteriófagos , Escherichia coli O157 , Humanos , Escherichia coli O157/genética , Bacteriófagos/genética , Genoma , Genômica , Sequência de BasesRESUMO
[This corrects the article DOI: 10.1007/s11908-022-00788-z.].
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Genomic compaction is an essential characteristic of living organisms. Nucleoid-associated proteins (NAPs) are a group of small proteins that play crucial roles in chromosome architecture and affect DNA replication, transcription, and recombination by imposing topological alterations in genomic DNA, thereby modulating global gene expression. EbfC/YbaB was first described as a DNA-binding protein of Borrelia burgdorferi that regulates the expression of surface lipoproteins with roles in virulence. Further studies indicated that this protein binds specifically and non-specifically to DNA and colocalises with nucleoids in this bacterium. The data showed that this protein binds to DNA as a homodimer, although it can form other organised structures. Crystallography analysis indicated that the protein possesses domains responsible for protein-protein interactions and forms a "tweezer" structure probably involved in DNA binding. Moreover, sequence analysis revealed conserved motifs that may be associated with dimerisation. Structural analysis also showed that the tridimensional structure of EbfC/YbaB is highly conserved within the bacterial domain. The DNA-binding activity was observed in different bacterial species, suggesting that this protein can protect DNA during stress conditions. These findings indicate that EbfC/YbaB is a broadly distributed NAP. Here, we present a review of the existing data on this NAP.
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Purpose of Review: The COVID-19 pandemic has been responsible for more than 6.3 million deaths worldwide. During the pandemic, the indiscriminate use of antibiotics has increased, contributing to the spread of multidrug-resistant bacteria. In this review, we aim to determine the spread and impact of antibiotic treatments in patients with COVID-19, focusing on underdeveloped and developing countries. Recent Findings: Meta-analysis revealed that bacterial co-infections and secondary infections are relatively rare in COVID-19 patients, corresponding to less than 20% of hospitalized patients. Even so, most of these patients have received antibiotic treatments. Summary: This review discusses how the COVID-19 pandemic could increase the emergence of multidrug-resistant strains to currently available antibiotics. Initially, we discussed the spread and impact of multidrug resistance of ESKAPE pathogens associated with nosocomial infections and analyzed their risk of secondary infections in patients with COVID-19. Then we highlight three factors related to the spread of resistant bacteria during the current pandemic: overprescription of antibiotics followed by self-medication. Finally, we discussed the lack of availability of diagnostic tests to discriminate the etiologic agent of a disease. All these factors lead to inappropriate use of antibiotics and, therefore, to an increase in the prevalence of resistance, which can have devastating consequences shortly. The data compiled in this study underscore the importance of epidemiological surveillance of hospital isolates to provide new strategies for preventing and controlling infections caused by multidrug-resistant bacteria. In addition, the bibliographic research also highlights the need for an improvement in antibiotic prescribing in the health system.
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Endolysins are bacteriophage-derived lytic enzymes with antimicrobial activity. The action of endolysins against Gram-negative bacteria remains a challenge due to the physical protection of the outer membrane. However, recent research has demonstrated that signal-anchor-release (SAR) endolysins permeate the outer membrane of Gram-negative bacteria. This study investigates 2628 putative endolysin genes identified in 183,298 bacteriophage genomes. Previously, bioinformatic approaches resulted in a database of 66 SAR endolysins. This manuscript almost doubles the list with 53 additional SAR endolysin candidates. Forty-eight of the putative SAR endolysins described in this study contained one muramidase catalytic domain, and five included additional cell wall-binding domains at the C-terminus. For the moment, SAR domains are found in four protein families: glycoside hydrolase family 19 (GH19), glycoside hydrolase family 24 (GH24), glycoside hydrolase family 25 (GH25), and glycoside hydrolase family 108 (GH108). These SAR lysis are clustered in eight groups based on biochemical properties and domain presence/absence. Therefore, in this study, we expand the arsenal of endolysin candidates that might act against Gram-negative bacteria and develop a consult database for antimicrobial proteins derived from bacteriophages.
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Anti-Infecciosos , Bacteriófagos , Anti-Infecciosos/metabolismo , Bacteriófagos/genética , Bacteriófagos/metabolismo , Endopeptidases/química , Endopeptidases/genética , Glicosídeo Hidrolases/metabolismo , Bactérias Gram-Negativas , MetagenômicaRESUMO
Carnobacterium maltaromaticum is a non-starter lactic acid bacterium (LAB) of interest in the dairy industry for biopreservation. This study investigated the interference competition network and the specialized metabolites biosynthetic gene clusters (BGCs) content in this LAB in order to explore the relationship between the antimicrobial properties and the genome content. Network analysis revealed that the potency of inhibition tended to increase when the inhibition spectrum broadened, but also that several strains exhibited a high potency and narrow spectrum of inhibition. The C. maltaromaticum strains with potent anti-L. monocytogenes were characterized by high potency and a wide intraspecific spectrum. Genome mining of 29 strains revealed the presence of 12 bacteriocin BGCs: four of class I and eight of class II, among which seven belong to class IIa and one to class IIc. Overall, eight bacteriocins and one nonribosomal peptide synthetase and polyketide synthase (NRPS-PKS) BGCs were newly described. The comparison of the antimicrobial properties resulting from the analysis of the network and the BGC genome content allowed us to delineate candidate BGCs responsible for anti-L. monocytogenes and anti-C. maltaromaticum activity. However, it also highlighted that genome analysis is not suitable in the current state of the databases for the prediction of genes involved in the antimicrobial activity of strains with a narrow anti-C. maltaromaticum activity.
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Cronobacter spp. is an opportunistic pathogen that causes severe infections, affecting newborns and infants, and is also an emerging cause of hospital-acquired infection in elderly populations. These infections are mainly associated with the consumption of infant formulas, even though these bacteria have been isolated from other foods as well. Cronobacter spp. invades epithelial cells and escapes the immune response mechanisms, multiplying inside macrophages. However, the pathogenesis and virulence factors of these bacteria have not been fully elucidated and need to be further studied. Therefore, this study aimed to evaluate the ability of Cronobacter spp. strains isolated from infant cereals to invade and survive within macrophages, investigate the virulence phenotype using the Galleria mellonella model, and identify possible genes involved in bacterial pathogenesis through pan-genome analysis. All the isolates were able to invade macrophages and the survival of bacteria decreased over a 72 h period, with bacterial cell counts reaching up to 106 CFU/ml. Cronobacter sakazakii isolate 112 exhibited a similar mortality rate (40-70%) to the ATCC BAA 894 strain (Cronobacter sakazakii) in G. mellonella assay. In addition, some unique virulence genes (isolate 7, ada_2, tcmA_1, acrB_3; isolate 78, ampC_2, rihC_1 and isolate 112, fimH, ylpA, gtrA) were identified within isolates with the invasive profile in the in vivo and in vitro assays. Furthermore, isolates from different species were grouped into seven distinct clusters in the pan-genome analysis. The most virulent isolates (7, 78, and 112) were grouped in distinct subclusters in the cladogram. This work revealed potential Cronobacter spp. pathogenic strains recovered from infant cereals.
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Cronobacter sakazakii , Cronobacter , Idoso , Cronobacter/genética , Grão Comestível , Microbiologia de Alimentos , Humanos , Lactente , Fórmulas Infantis , Recém-Nascido , Análise de Sequência de DNA , Virulência/genéticaRESUMO
In this study, we have presented the genomic characterisation of UFJF_PfDIW6, a novel lytic Pseudomonas fluorescens-phage with potential for biocontrol in the dairy industry. This phage showed a short linear double-stranded DNA genome (~42 kb) with a GC content of 58.3% and more than 50% of the genes encoding proteins with unknown functions. Nevertheless, UFJF_PfDIW6's genome was organised into five functional modules: DNA packaging, structural proteins, DNA metabolism, lysogenic, and host lysis. Comparative genome analysis revealed that the UFJF_PfDIW6's genome is distinct from other viral genomes available at NCBI databases, displaying maximum coverages of 5% among all alignments. Curiously, this phage showed higher sequence coverages (38-49%) when aligned with uncharacterised prophages integrated into Pseudomonas genomes. Phages compared in this study share conserved locally collinear blocks comprising genes of the modules' DNA packing and structural proteins but were primarily differentiated by the composition of the DNA metabolism and lysogeny modules. Strategies for taxonomy assignment showed that UFJF_PfDIW6 was clustered into an unclassified genus in the Podoviridae clade. Therefore, our findings indicate that this phage could represent a novel genus belonging to the Podoviridae family.
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Bacteriófagos , Podoviridae , Fagos de Pseudomonas , Pseudomonas fluorescens , Bacteriófagos/genética , DNA , DNA Viral/genética , Indústria de Laticínios , Genoma Viral , Filogenia , Podoviridae/genética , Fagos de Pseudomonas/genética , Pseudomonas fluorescens/genéticaRESUMO
Salmonella enterica causes Salmonellosis, an important infection in humans and other animals. The number of multidrug-resistant (MDR) phenotypes associated with Salmonella spp. isolates is increasing worldwide, causing public health concern. Here, we aim to characterize the antimicrobial-resistant phenotype of 789 non-typhoidal S. enterica strains isolated from human infections in the state of São Paulo, Brazil, along 20 years (2000-2019). Among the non-susceptible isolates, 31.55, 14.06, and 13.18% were resistant to aminoglycosides, tetracycline, and ß-lactams, respectively. Moreover, 68 and 11 isolates were considered MDR and Extended Spectrum ß-Lactamase (ESBL) producers, respectively, whereas one isolate was colistin-resistant. We selected four strains to obtain a draft of the Genome Sequence; one S. Infantis (ST32), one S. Enteritidis (ST11), one S. I 4,[5],12:i:- (ST19), and one S. Typhimurium (ST313). Among them, three presented at least one of the following antimicrobial resistance genes (AMR) linked to mobile DNA: blaTEM-1B, dfrA1, tetA, sul1, floR, aac(6')-laa, and qnrE1. This is the first description of the plasmid-mediated quinolone resistance (PMQR) gene qnrE1 in a clinical isolate of S. I 4,[5],12:i:-. The S. Typhimurium is a colistin-resistant isolate, but did not harbor mcr genes, but it presented mutations within the mgrB, pmrB, and pmrC regions that might be linked to the colistin-resistant phenotype. The virulence pattern of the four isolates resembled the virulence pattern of the highly pathogenic S. Typhimurium UK-1 reference strain in assays involving the in vivo Galleria mellonella model. In conclusion, most isolates studied here are susceptible, but a small percentage present an MDR or ESBL-producer and pathogenic phenotype. Sequence analyses revealed plasmid-encoded AMR genes, such as ß-lactam and fluoroquinolone resistance genes, indicating that these characteristics can be potentially disseminated among other bacterial strains.
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Farmacorresistência Bacteriana , Infecções por Salmonella , Salmonella enterica , Antibacterianos/farmacologia , Brasil , Colistina/farmacologia , Farmacorresistência Bacteriana/genética , Farmacorresistência Bacteriana Múltipla/genética , Patrimônio Genético , Humanos , Testes de Sensibilidade Microbiana , Infecções por Salmonella/microbiologia , Salmonella enterica/genéticaRESUMO
The prevalence of multidrug-resistant Gram-negative bacteria is a public health concern. Bacteriophages and bacteriophage-derived lytic enzymes have been studied in response to the emergence of multidrug-resistant bacteria. The availability of tRNAs and endolysin toxicity during recombinant protein expression is circumvented by codon optimization and lower expression levels using inducible pET-type plasmids and controlled cultivation conditions, respectively. The use of polyhistidine tags facilitates endolysin purification and alters antimicrobial activity. Outer membrane permeabilizers, such as organic acids, act synergistically with endolysins, but some endolysins permeate the outer membrane of Gram-negative bacteria per se. However, the outer membrane permeation mechanisms of endolysins remain unclear. Other strategies, such as the co-administration of endolysins with polymyxins, silver nanoparticles, and liposomes confer additional outer membrane permeation. Engineered endolysins comprising domains for outer membrane permeation is also a strategy used to overcome the current challenges on the control of multidrug-resistant Gram-negative bacteria. Metagenomics is a new strategy for screening endolysins with interesting antimicrobial properties from uncultured phage genomes. Here, we review the current state of the art on the heterologous expression of endolysin, showing the potential of bacteriophage endolysins in controlling bacterial infections.
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Treatment of infections caused by multidrug-resistant (MDR) Gram-negative bacteria is challenging, a potential solution for which is the use of bacteriophage-derived lytic enzymes. However, the exogenous action of bacteriophage lysins against Gram-negative bacteria is hindered due to the presence of an impermeable outer membrane in these bacteria. Nevertheless, recent research has demonstrated that some lysins are capable of permeating the outer membrane of Gram-negative bacteria with the help of signal peptides. In the present study, we investigated the genomes of 309 bacteriophages that infect Gram-negative pathogens of clinical interest in order to determine the evolutionary markers of signal peptide-containing lysins. Complete genomes displayed 265 putative lysins, of which 17 (6.41%) contained signal-arrest-release motifs and 41 (15.47%) contained cleavable signal peptides. There was no apparent relationship between host specificity and lysin diversity. Nevertheless, the evolution of lysin genes might not be independent of the rest of the bacteriophage genome once pan-genome clustering and lysin diversity appear to be correlated. In addition, signal peptide- and signal-arrest-release-containing lysins were monophyletically distributed in the protein cladogram, suggesting that the natural selection of holin-independent lysins is divergent. Our study screened 58 (21.89%) out of 265 potential candidates for in vitro experimentation against MDR bacteria.
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Bacteriófagos/enzimologia , Bacteriófagos/genética , Bactérias Gram-Negativas/virologia , Sinais Direcionadores de Proteínas , Proteínas Virais/genética , Motivos de Aminoácidos , Membrana Externa Bacteriana , Bacteriólise , Biodiversidade , Farmacorresistência Bacteriana Múltipla , Evolução Molecular , Genoma Bacteriano , Genoma Viral , Bactérias Gram-Negativas/genética , Proteínas Virais/isolamento & purificaçãoRESUMO
The bacteriophage UFV-AREG1 was used as a model organism to evaluate the encapsulation via extrusion using different hydrocolloids. Pure alginate [0.75%, 1.0%, 1.5% and 2.0% (m/v)] and mixtures of alginate [0.75% or 1.0% (m/v)] with carrageenan [1.25% (m/v)], chitosan [0.5% (m/v)], or whey protein [1.5% (m/v)] were used to produce bacteriophage-loaded beads. The encapsulating solutions presented flow behavior of non-Newtonian pseudoplastic fluids and the concentration of hydrocolloid did not influence (p > 0.05) the morphology of the beads, except for alginate-chitosan solutions, which presented the higher flow consistency index (K) and the lower flow behavior index (n). The encapsulation efficiency was about 99% and the confocal photomicrography of the encapsulated bacteriophages labeled with fluorescein isothiocyanate showed homogenous distribution of the viral particles within the beads. The phages remained viable in the beads of alginate-whey protein even when submitted to pH 2.5 for 2 h. Beads incubated directly in simulated intestinal fluid (pH 6.8) resulted in a minimal of 50% release of the UFV-AREG1 phages after 5 min, even when previously submitted to the simulated gastric fluid (pH 2.5). Encapsulation enabled phages to remain viable under refrigeration for five months. Encapsulated UFV-AREG1 phages were sensitive to dehydration, suggesting the need for protective agents. In this study, for the first-time bacteriophages were encapsulated in alginate-carrageenan beads, as well as alginate-chitosan as a bead-forming hydrocolloid. In addition, a novel procedure for encapsulating bacteriophages in alginate-whey protein was proposed. The assembled system showed efficiency in the encapsulation of UFV-AREG1 bacteriophages using different hydrocolloids and has potential to be used for the entrapment of a variety of bioactive compounds.
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Alginatos , Bacteriófagos , Preparações de Ação Retardada , Ácido Glucurônico , Ácidos Hexurônicos , PolímerosRESUMO
The microbiota contributes to artisanal cheese bioprotection and biopreservation through inter and intraspecific competition. This work aimed to investigate the phylogenetic distribution of the repertoire of bacteriocin structural genes of model lactic acid bacteria (LAB) in order to investigate its respective role in the artisanal cheeses microenvironment. A phylogenetic analysis of the rRNA 16S gene from 445 model strains of LAB was conducted using bayesian inference and the repertoire of bacteriocin genes was predicted from these strains by BAGEL software. Bacterial strains were clustered in five monophyletic clades (A, B, C, D and E) with high posterior probability values (PPâ¯>â¯0.99). One bacteriocin structural gene was predicted for 88.5% of the analyzed strains. The majority of the species encoded different classes of bacteriocins. Greater diversity of bacteriocin genes was found for strains included in clade A, comprising Lactococcus lactis, Streptococcus agalactiae, Streptococcus thermophilus, Streptococcus macedonicus, Enterococcus faecalis and Enterococcus faecium. In addition, Lactococcus lactis presented higher diversity of bacteriocin classes, encoding glycocins, lanthipeptides, sactipeptides, cyclic and linear azole-containing peptides, included in bacteriocins class I, besides class II and III. The results suggest that the distribution of bacteriocin structural genes is related to the phylogenetic clades of LAB species, with a higher frequency in some specific clades. Information comprised in this study contributes to comprehend the bacterial competition mechanisms in the artisanal cheese microenvironment.
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Bacteriocinas/metabolismo , Queijo/microbiologia , Lactobacillales/genética , Lactobacillales/metabolismo , Bacteriocinas/química , Bacteriocinas/genética , Microbiologia de Alimentos , Genoma Bacteriano , Peptídeos/química , Peptídeos/classificação , Peptídeos/metabolismo , Peptídeos/farmacologia , FilogeniaRESUMO
The indiscriminate use of antibiotics and the emergence of resistant microorganisms have become a major challenge for the food industry. The purpose of this work was to microencapsulate the bacteriophage UFV-AREG1 in a calcium alginate matrix using microfluidic devices and to study the viability and efficiency of retention. The microcapsules were added to gel of propylene glycol for use as an antimicrobial in the food industry. The technique showed the number of the phage encapsulation, yielding drops with an average 100-250µm of diameter, 82.1±2% retention efficiency and stability in the gel matrix for 21days. The gel added to the microencapsulated phage showed efficiency (not detectable on the surface) in reducing bacterial contamination on the surface at a similar level to antimicrobial chemicals (alcohol 70%). Therefore, it was possible to microencapsulate bacteriophages in alginate-Ca and apply the microcapsules in gels for use as sanitizers in the food industry.
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Dispositivos Lab-On-A-Chip , Alginatos/química , Bacteriófagos/química , Cápsulas/química , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Tamanho da PartículaRESUMO
Here, we present the genome sequence of the Escherichia coli bacteriophage UFV-AREG1. This phage was isolated from cowshed wastewater and showed specificity for enterohemorrhagic E. coli O157:H7 (ATCC 43895), E. coli 0111 (CDC O11ab) and E. coli (ATCC 23229).